Vegetation Biomass, NDVI, and LAI along the Eurasian Arctic Transect

Howard E. Epstein, Donald A. Walker, Gerald V. Frost, Martha K. Raynolds, and Uma S. Bhatt

ICOP 2016 - Potsdam, Germany

(Photo H.E. Epstein)

IGBP High-Latitude Transects

McGuire et al. 2002 (Journal of Vegetation Science)

- Few data points

- Data don’t go very “high”

Spatial Patterns of Tundra Vegetation

The Arctic Tundra

Biome

Walker, D. A., 2005. The Circumpolar Arctic Vegetation

Map. Journal of Vegetation Science.

1) Field observations of vegetation

biomass, NDVI, and LAI along

the Yamal Peninsula, Siberia

and beyond (the EAT)

2) Satellite remote sensing of

vegetation trends along the EAT

3) Satellite remote sensing of

vegetation trends throughout

Eurasia

Presentation Topics

Raynolds et al. (2012), Walker et al. (2012)

Eurasian Arctic Transect

Subzone E

Subzone D

Subzone C

Subzone B

Subzone A

(Photos D.A. Walker and H.E. Epstein)

Eurasian Arctic Transect Location Data

Field Data Collection

- six locations, with 2-3 sites at each

location with varying soil textures

- 50 x 50 m sampling grid and five 50 m

transects at each site

- NDVI (ASD PSII) at 1-m intervals along the

transects

- LAI (Li-Cor LAI-2000) at 1-m intervals along

the transects

- five aboveground biomass harvests

- five soil samples (top 10 cm)

y = 0.0129x1.0415 r² = 0.8991

0

0.2

0.4

0.6

0.8

1

1.2

0 10 20 30 40 50

LAI

SWI

LAI

y = 0.4322x0.0949 r² = 0.8057

0.45

0.5

0.55

0.6

0.65

0.7

0 10 20 30 40 50

ND

VI

SWI

NDVI

y = 17.216x0.7247 r² = 0.9104

0

50

100

150

200

250

300

350

400

0 10 20 30 40 50

Bio

mas

s (g

m-2

)

SWI

Overstory Biomass

y = 19.636x + 40.341 r² = 0.8507

0

200

400

600

800

1000

1200

0 10 20 30 40 50

Bio

mas

s (g

m-2

)

SWI

Total Live Biomass

0

200

400

600

800

1000

1200N

adym

-1

Nad

ym-2

a

Nad

ym-2

b

Lab

oro

vaya

-1

Lab

oro

vaya

-2

Vas

kin

y-…

Vas

kin

y-…

Vas

kin

y-…

Kh

aras

ave

y-1

Kh

aras

ave

y-2

a

Kh

aras

ave

y-…

Ost

rov-

…

Ost

rov-

Be

lyy-

2

Kre

nke

l-1

Kre

nke

l-2

Bio

mas

s g

/m²

Total live biomass excluding trees and cryptogamic crusts

Deciduous shrub

Evergreen shrub

Forb

Graminoid

Lichen

Moss

Aboveground biomass by plant functional type (Walker et al. 2012)

SOUTH NORTH

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0S

WI

(◦C

mo

nth

s)

- High Arctic (Subzones C and B) sites on the Yamal are warmer than comparable

subzonal sites in North America

y = -0.6604x2 + 30.822x - 30.676 r² = 0.8616

0

100

200

300

400

500

0 10 20 30 40 50

Bio

mas

s (g

m-2

)

SWI

Moss Biomass

y = 11.144x0.8478 r² = 0.7839

0

200

400

600

800

0 10 20 30 40 50

Bio

mas

s (g

m-2

)

SWI

Lichen Biomass

y = 0.0026x3.177 r² = 0.9386

0

100

200

300

400

500

0 10 20 30 40 50

Bio

mas

s (g

m-2

)

SWI

Shrub Biomass

y = 24.893x0.8586 r² = 0.8826

0

200

400

600

800

0 20 40 60

Bio

mas

s (g

m-2

)

SWI

Non-Vascular Biomass

y = -0.0065x + 2.0615 r² = 0.0428

0

0.5

1

1.5

2

2.5

3

0 10 20 30 40 50

% C

arb

on

SWI

%C

y = 0.199x r² = 0.6026

02468

10121416

0 10 20 30 40 50

Dep

th (

cm)

SWI

Organic Layer Depth

y = 24.339x0.3857 r² = 0.8043

0

20

40

60

80

100

120

140

160

0 10 20 30 40 50

Dep

th (

cm)

SWI

Active Layer Depth

SOILS

y = 0.6389x + 11.586 r² = 0.6977

0

10

20

30

40

50

0 10 20 30 40 50

C:N

SWI

C:N

y = -0.019ln(x) + 0.1392 r² = 0.2082

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 10 20 30 40 50

%N

itro

gen

SWI

%N

Temporal Dynamics of Temperature (SWI) and NDVI for the Eurasian Arctic Transect

- TI (temporally integrated) –NDVI is an indicator of cumulative growing season productivity

- The Eurasian Arctic Transect has experienced substantive warming further north and generally slight cooling on the Yamal Peninsula from 1982-2015

- The Eurasian Arctic Transect has exhibited slight “greening” in the southern part of the Yamal Peninsula and “browning” in the northern part of the Peninsula

- Again, substantive warming in Subzones A and B with slight cooling in Subzones C-E on the Yamal Peninsula from 1982-2015

- Field sites within each subzone do not always exhibit the same trends compared to the subzone as a whole (e.g. Kharasavey)

-1

0

1

2

1980 1990 2000 2010Re

lati

ve C

han

ge

A

B

C

D

E

North America Eurasia

SWI

NDVI

-1

-0.5

0

0.5

1

1.5

1980 1990 2000 2010

Re

lati

ve C

han

ge

-0.5

-0.25

0

0.25

0.5

1980 1990 2000 2010

Re

lati

ve C

han

ge

-0.4

-0.2

0

0.2

0.4

0.6

1980 1990 2000 2010

Re

lati

ve C

han

ge

-0.2

0

0.2

0.4

0.6

1980 1990 2000 2010Re

lati

ve C

han

ge

-1

0

1

2

3

1980 1990 2000 2010Re

lati

ve C

han

ge

-0.4

-0.2

0

0.2

0.4

1980 1990 2000 2010

Re

lati

ve C

han

ge

-0.4

-0.2

0

0.2

0.4

1980 1990 2000 2010

Re

lati

ve C

han

ge

-0.2

0

0.2

0.4

1980 1990 2000 2010Re

lati

ve C

han

ge

-0.2

0

0.2

0.4

1980 1990 2000 2010Re

lati

ve C

han

ge

-0.035

-0.03

-0.025

-0.02

-0.015

-0.01

-0.005

0

0.005

A B C D E

Dif

fere

nce b

etw

een

rela

tiv

e c

han

ge

in N

DV

I an

d S

WI S

lop

e

Subzone

North America Eurasia

Temporal Dynamics of Temperature (SWI) and MaxNDVI (peak season) for Eurasia

-1

0

1

2

3

4

5

6

7

A B C D E

Av

era

ge C

han

ge i

n S

WI

fr

om

1982-2

013

Subzone

NAmer

Eurasia

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

A B C D E

Av

era

ge C

han

ge i

n N

DV

I f

rom

1982

-2013

Subzone

NAmer

Eurasia

-20

0

20

40

60

80

100

A B C D EAv

era

ge P

erc

en

t C

han

ge i

n S

WI

fr

om

1982-2

013

Subzone

NAmer

Eurasia

-10

-5

0

5

10

15

20

25

30

A B C D E

Av

era

ge P

erc

en

t C

han

ge i

n N

DV

I

fro

m 1

982-2

013

Subzone

NAmer

Eurasia

MaxNDVI SWI

A

B

C

D

E

North America Eurasia

-0.03

-0.01

0.01

0.03

-8 -6 -4 -2 0 2 4 6

ND

VI

ch

an

ge

SWI change

-0.02

0.00

0.02

-8 -6 -4 -2 0 2 4 6 8

ND

VI

ch

an

ge

SWI change

-0.04

0.01

0.06

-9 -7 -5 -3 -1 1 3 5 7ND

VI

ch

an

ge

SWI change

-0.04

-0.02

0.00

0.02

0.04

0.06

-11 -9 -7 -5 -3 -1 1 3 5 7 9 11

ND

VI

ch

an

ge

SWI change

-0.03

-0.01

0.01

0.03

-13-11 -9 -7 -5 -3 -1 1 3 5 7 9 11 13 15

ND

VI

ch

an

ge

SWI change

-0.03

-0.01

0.01

0.03

-3 -2 -1 0 1 2 3

ND

VI

ch

an

ge

SWI change

-0.09

-0.05

-0.01

0.03

0.07

-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7

ND

VI

ch

an

ge

SWI change

-0.09

-0.05

-0.01

0.03

0.07

0.11

-10 -8 -6 -4 -2 0 2 4 6 8

ND

VI

ch

an

ge

SWI change

-0.05

-0.02

0.01

0.04

0.07

-10 -8 -6 -4 -2 0 2 4 6 8

ND

VI

ch

an

ge

SWI change

-0.05

-0.03

-0.01

0.01

0.03

-10 -8 -6 -4 -2 0 2 4 6 8N

DV

I c

ha

ng

e

SWI change

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

A B C D E

Reg

ressio

n s

lop

e o

f S

WI

an

d N

DV

I ch

an

ge f

rom

pre

vio

us y

ear

Subzone

North America Eurasia

Inter-annual Changes in Temperature (SWI) and MaxNDVI (peak season) for Eurasia

Raynolds et al. (2012)

Integration of field and remote sensing data still presents a major challenge - Inherent differences in

resolutions and extents of the data

- Landscape heterogeneity vs. field sampling scheme (e.g. zonal vegetation)

Conclusions

- A collection of field locations along a latitudinal gradient in northwestern Siberia, Russia

(EAT) was used to evaluate the spatial patterns of vegetation and soils properties along a

summer warmth index (SWI) gradient

- NDVI, LAI, total biomass, shrub biomass, and total non-vascular biomass all increased with

increasing SWI; mosses had their greatest biomass at intermediate values of SWI

- C:N ratio (mineral soil), organic layer thickness, and active layer thickness all increased with

increasing SWI

- With regard to temporal dynamics, the Higher Arctic of the EAT has warmed substantively

since 1982, where the mainland Yamal Peninsula has experience a general slight cooling; the

northern Yamal has showed “browning” trends, whereas the southern Yamal has “greened”

- The northernmost subzones in Eurasia have shown substantial warming with minimal

vegetation response, whereas the southernmost areas have show the greatest vegetation

increases with essentially no warming

- Vegetation in Subzone B (along the EAT) is the most response with regard to inter-annual

variability in SWI

This work was funded by the NASA Land-Cover Land-Use Change (LCLUC) program, Grant Nos. NNG6GE00A, NNX09AK56G, NNX14AD906, and NSF Grant Nos. ARC-0531180 (part of the Synthesis of Arctic System Science initiative - Greening of the Arctic) and ARC-0902152 (part of the Changing Seasonality of Arctic Systems initiative)